The piloting and guidance of an aircraft, whether manual or automatic, require the provision of precise information on different flight parameters, such as the altitude, airspeed, ground speed, attitude and incline of the aircraft.
The flight parameters are computed from information collected by measuring sensors.
The reliability of the information provided on the flight parameters is critical for proper progression of the flight. In fact, these parameters are used not only directly by the pilot, when the latter takes the controls of the aircraft, but also by the computers intended to control the aircraft automatically, in particular to control the fly-by-wire system, automatic pilots, or automatic guides.